Making a menu selection

Hi,

I am trying to make a menu selection SUB that will not exit until select button is pressed. I am using the PIC18F4550

Code:

---

Selection var PortC.6
Next1 var PortC.7
'///////////////////////////////////// 
'///////  GetModeOfOperation  ////////
'/////////////////////////////////////
GetModeOfOperation:

        Lookup Op_Mode, [55,65],Operation_Mode
       
        Select Case Operation_Mode
        Case 55                                                               
                lcdout $FE,1,  " Charger Mode "
        Case 65                                                               
                lcdout $FE,1,  " Recycle Mode"
        End Select
       
                lcdout $FE,$C0, "Next or Select"
                pause 200
               
                if Selection=1 then return
                if Next1=1 then Op_Mode = Op_Mode + 1
                if Op_Mode > 1 then Op_Mode = 0
                Gosub GetModeOfOperation

Return

---

The problem, is that my sub routine exits (return) after 4 seconds while nothing has been pressed.

Quote:

---

Originally Posted by lerameur

Hi,

I am trying to make a menu selection SUB that will not exit until select button is pressed. I am using the PIC18F4550

Code:

---

Selection var PortC.6
Next1 var PortC.7
'///////////////////////////////////// 
'///////  GetModeOfOperation  ////////
'/////////////////////////////////////
GetModeOfOperation:

        Lookup Op_Mode, [55,65],Operation_Mode
       
        Select Case Operation_Mode
        Case 55                                                               
                lcdout $FE,1,  " Charger Mode "
        Case 65                                                               
                lcdout $FE,1,  " Recycle Mode"
        End Select
       
                lcdout $FE,$C0, "Next or Select"
                pause 200
               
                if Selection=1 then return
                if Next1=1 then Op_Mode = Op_Mode + 1
                if Op_Mode > 1 then Op_Mode = 0
                Gosub GetModeOfOperation

Return

---

The problem, is that my sub routine exits (return) after 4 seconds while nothing has been pressed.

---

I just learned today that in th 18's you can overflow the stack. I don't really know the what happens when you do, but I suspect a "reset" maybe. Anyhow, I think the gosub needs to be a goto. otherwise you just keep calling itself without a return. everytime it saves PC to the stack, but never reads it back.

ok wow work great now, thank you

K

This should help you.

Quote:

---

Originally Posted by lerameur

a menu selection SUB that will not exit until select button is pressed.

---

Code:

---

Selection var PortC.6

Next1 var PortC.7

'///////////////////////////////////// 
'///////  GetModeOfOperation  ////////
'/////////////////////////////////////
GetModeOfOperation:
    while Selection = 0          ' exit when selection becomes 1

        Lookup Op_Mode, [55,65],Operation_Mode
       
        Select Case Operation_Mode
        Case 55                                                               
                lcdout $FE,1,  " Charger Mode "
        Case 65                                                               
                lcdout $FE,1,  " Recycle Mode"
        End Select
       
                lcdout $FE,$C0, "Next or Select"
                pause 200
               
                if Next1=1 then Op_Mode = Op_Mode + 1
                if Op_Mode > 1 then Op_Mode = 0
    wend
    Return

---